A gear arrangement with a built-up gear is known, for example, from WO 01/44694 A1. A gear, which is intended for being mounted on a shaft or a pinion and which comprises a gear rim, which is arranged between two flanges, is described in the document, and the gear rim has a two-part design concerning its radial extension. The two segments of the gear rim are connected in the course of mounting by means of screws, which are passed through the segments of the gear rim at right angles to the longitudinal axis of the pinion or the shaft. The gear rim is mounted together with the flanges arranged axially on both sides on the shaft or the pinion, and its segments enclose a hub formed at one of the flanges. The holding together of the built-up gear axially is likewise brought about by means of screws, which are passed through the gear rim in parallel to the longitudinal axis of the pinion or of the shaft to connect the two flanges. The drawback of this arrangement is the comparatively great effort needed for mounting, but especially the fact that the arrangement is not self-centering in respect to the position of the built-up gear in relation to the shaft or the pinion.
By contrast, the gear arrangements known from EP 1 339 596 B1 and WO 2005/038303 A1, which are likewise embodied with a built-up gear, have the advantage that due to a special design of the components of the built-up gear, they are self-centering. The two outer disks or flanges, which form the gear together with the gear rim, have axially extending projections in these, which pass through the gear rim and mesh with corresponding depressions of the respective other opposite outer disk. Self-centering, which leads to improved power transmission, is achieved as a result. Despite the fact that, moreover, the mounting of the gear is facilitated by the embodiment, the effort needed for mounting still remains high because the components of the built-up gear are screwed or riveted together to achieve reliable holding together in the solutions disclosed in the above-mentioned documents, for which corresponding screws or rivets are passed through additional holes provided for this purpose in a radially inner area of the gear rim. In addition, the large number of holes to be provided for the positive-locking connection of the flanges, on the one hand, and for the screws or rivets at the gear rim, on the other hand, is to be considered to be disadvantageous with respect to the preparation of these holes in an injection molding process. The gear rim does not have, to some extent, a design suitable for plastics in this respect.